U.S. joins lawsuit against Lance Armstrong

2/22/13 1:09 PM EST

The U.S. is joining a civil lawsuit charging disgraced cycling champion Lance Armstrong with bilking the U.S. Postal Service out of endorsement money accepted while Armstrong was using performance-enhancing drugs, an attorney for Armstrong said Friday.

The so-called "qui tam" suit was filed by former Armstrong teammate Floyd Landis under the provisions of a federal law that allows any person to sue over alleged fraud aimed at the government.

However, Armstrong lawyer Robert Luskin contends the suit is without merit because, despite Armstrong's recent admission of doping, the Postal Service realized a lot of benefit from the deal with the cycling team.

"Lance and his representatives worked constructively over these last weeks with federal lawyers to resolve this case fairly, but those talks failed because we disagree about whether the Postal Service was damaged. The Postal's Services own studies show that the Service benefited tremendously from its sponsorship —benefits totaling more than $100 million," Luskin said in a statement.

The Justice Department is expected to pursue damages from Armstrong as well as his manager Johan Bruyneel and Tailwind Sports. Landis could receive between 15 percent and 25 percent of any money the U.S. Government recovers.

Federal prosecutors in Los Angeles have also been exploring possible criminal charges arising from the doping episode. The status of that probe is unclear, but Armstrong's lawyers complained to a judge there about repeated leaks to the news media.